The present invention relates to improvements in hydraulic pumps of the swash plate type, that is to say pumps comprising a plurality of pistons arranged in a circle, these pistons bearing against a plate driven by a driving shaft, the plate being inclined relatively to the driving shaft in such a manner that the pistons are given a reciprocating movement when the plate is driven by the shaft.
The improvements according to the present invention are intended to improve the volumetric efficiency of the pump, improving on the one hand the fluid admission conditions and on the other hand the fluid discharge conditions from the pump, more particularly for multiple-delivery pumps.
In order to improve the supply conditions for the pump, it has already been proposed in French Pat. No. 1,409,274 to partly hollow out the swash plate in order to obtain a centrifuging effect on the hydraulic liquid, which accelerates the flow of the said liquid; futhermore in French Pat. No. 71,20091 there was described a pump wherein the liquid arrives directly at the centre of the swash plate by means of a bore formed in the middle of the circle of pistons.
These two arrangements combined with one another have already allowed a very considerable improvement in the delivery of the pump at high speeds of rotation but, the aim of the present invention, is to provide a still greater improvement by using an additional centrifuging effect produced by a taper roller bearing situated in the pump to absorb the mechanical stresses produced by the reaction of the pistons on the rotating swash plate.